Photosynthesis/cellular respiration

NADP+ is the final
electron acceptor in the electron transfer chain of the light reactions. It carries its high-energy electrons to the
Calvin cycle. Thus is a source of energy
to power the Calvin cycle.

Without
oxygen, cellular respiration could not occur because oxygen serves as
the final electron acceptor in the electron transport system. The
electron transport system would therefore not be available.

Glycolysis can occur without oxygen. Although glycolysis does not
require oxygen, it does require NAD+. Cells without oxygen available
need to regenerate NAD+ from NADH so that in the absence of oxygen, at
least some ATP can be made by glycolysis.